Error Message: Command GIVE is not accepted within a procedure. Procedures may not produce a change in the world, they may only process logic.

I tried editing an inventory type script using the inventory command.But I didn't succeed.I can't find any more tutorials on Inventory for novices...

sorry.But I can't use Discord for some reason.

This is all I can find:"determine item" But I don't know how to specify a slot.

English is not my native language
Please forgive me if my statement in this post is not clear

I'm a newcomer
I don't know how to set items in a specific slot in the inventory
I looked up a lot of help documents
But I still can't
I hope someone can help me
thanks